B2: Organisation Flashcards

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1
Q

What does it mean if a cell is specialised?

A

they are adapted for a particular purpose

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2
Q

When do most animal cells differentiate?

A

in the early stages of development

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3
Q

When can most plant cells differentiate?

A

throughout their life

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4
Q

What happens as a cell differentiates?

A

-it may change shape
-different sub-cellular structures develop to enable it to carry out a specific function

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5
Q

How are sperm cells adapted to carry out their function?

A

they have many mitochondria (provide energy), they have an acrosome (contains enzymes to penetrate the outer layer of the egg), the nucleus only contains one set of genetic material and they have a tail

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6
Q

How is a root hair cell adapted for its function?

A

lots of mitochondria for active transport, large surface area to absorb water and minerals

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7
Q

What is a tissue?

A

a group of cells with a similar structure and function, which all work together to do a job

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8
Q

What is an organ?

A

a group of different tissues which all work together to perform a specific job

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9
Q

What is the role of muscle tissue in the stomach?

A

contracts to churn the contents

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10
Q

What is the role of glandular tissue in the stomach?

A

produce digestive juices

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11
Q

What is the role of epithelial tissue in the stomach?

A

cover the outside and inside of the stomach

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12
Q

What is an organ system?

A

a group of organs working together to do a particular job e.g the digestive system

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13
Q

What is an enzyme?

A

a biological catalyst; they speed up chemical reactions in living organisms

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14
Q

Name some of the properties of an enzyme.

A

-they are all large proteins
-there is a space within the protein molecule called the active site
-each enzyme catalyses a specific reaction
-they work best at a specific temperature and pH called the optimum

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15
Q

What is the ‘lock and key theory’?

A

a model used to explain how enzymes work

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16
Q

Describe the ‘lock and key theory’.

A

the chemical that reacts is called the substrate and it fits into the enzyme’s active site

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17
Q

What is denaturing?

A

when the shape of an enzyme is changed (by excessive temperature or pH) so that it no longer functions

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18
Q

What is amylase?

A

-produced in the salivary glands and pancreas
-is a carbohydrase that breaks down starch into sugar

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19
Q

What is protease?

A

-produced in the stomach, pancreas and small intestine
-breaks down proteins into amino acids

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20
Q

What is lipase?

A

-produced in the pancreas and small intestine
-breaks down lipids into fatty acids and glycerol

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21
Q

What is bile?

A

a liquid made in the liver and stored in the gall bladder. it is alkaline to neutralise hydrochloric acid from the stomach. it also emulsifies fat to form small droplets, increasing the surface area for enzymes to act on.

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22
Q

What is blood made out of?

A

a liquid called plasma, which has three different components suspended in it: red blood cells, white blood cells and platelets

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23
Q

What is the function of plasma?

A

transports various chemical substances around the body, such as the products of digestion, hormones, antibodies, urea and carbon dioxide

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24
Q

Describe a red blood cell.

A

-contains haemoglobin, which binds to oxygen to transport it from the lungs to the tissues and cells, which need it for respiration
-do not contain a nucleus, so there is more room for haemoglobin
-very small so they can fit through the capillaries
-shaped like biconcave discs,giving them a large surface area that oxygen can quickly diffuse across

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25
Q

Describe a white blood cell.

A

-helps the body protect against infection
-can change shape, so they can squeeze out of the blood vessels into the tissues or surround and engulf microorganisms

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26
Q

What are platelets?

A

fragments of cells, which collect at wounds and trigger blood clotting

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27
Q

What is an artery?

A

-takes blood away from the heart to the organs
-has thick walls made of elastic and muscle fibres, to resist the high pressure of the blood

28
Q

What is a vein?

A

-takes blood away from the organs back to the heart
-thinner walls and valves to prevent back-flow as the pressure is lower

29
Q

What is a capillary?

A

-join arteries to veins
-narrow vessels with walls that are one cell thick, to allow substances to be exchanged with the tissues

30
Q

What is a double circulatory system?

A

The type of blood system found in mammals, where the blood goes through the heart twice on each circuit of the body

31
Q

what are the four chambers in the heart?

A

-The left and right atria, which receive blood from the veins
-The left and right ventricles, which pump the blood out into arteries

32
Q

How does blood travel through the heart?

A

-Blood enters the heart through the atria
-The atria contract and force blood into the ventricles
-The ventricles, then contract and force blood out of the heart
-The valves make sure the blood flows in the correct direction
-The natural resting heart rate is controlled by a group of cells, located in the right atrium, which act as a pacemaker

33
Q

What is an artificial pacemaker?

A

electrical devices used to correct irregularities in the heart rate

34
Q

How does air reach the lungs?

A

through the trachea

35
Q

What are the alveoli?

A

air sacs in the lungs, oxygen diffuses out of them and carbon dioxide into them

36
Q

How are the alveoli adapted to carry out gas exchange?

A

-they have a large, moist surface area
-they have a very rich blood supply
-they are very close to the capillaries, so the distance for gases to diffuse is small

37
Q

What is good health?

A

a state of physical and mental wellbeing

38
Q

What is a disease?

A

a malfunction/infection of the body

39
Q

What does it mean if a disease is non-communicable?

A

it cannot be spread between organisms

40
Q

How can different diseases interact with each other?

A

-viruses infecting cells can be the trigger for cancers
-diseases of the immune system mean that an individual is more likely to catch infectious diseases
-immune reactions triggered by a pathogen can cause allergies
-if a person is physically ill, this can lead to poor mental health
-poor diet, stress and difficult life situations can increase the likelihood of developing certain diseases

41
Q

What is a risk factor?

A

a factor that will increase the chance of developing a disease

42
Q

What could a risk factor be?

A

an aspect of a person’s lifestyle or substances in the person’s body or environment

43
Q

What are the proven risk factors of cardiovascular disease?

A

lack of exercise/smoking/high intake of saturated fat

44
Q

What is a proven risk factor of type 2 diabetes?

A

obesity

45
Q

What is a proven risk factor of skin cancer?

A

ionising radiation e.g UV light

46
Q

What is a proven risk factor of low birthweight in babies?

A

smoking during pregnancy

47
Q

What is a proven risk factor of brain damage in babies?

A

excessive alcohol intake during pregnancy

48
Q

What happens when a person has coronary heart disease?

A

layers of fatty material buildup inside the coronary arteries and narrow them

49
Q

Give one of the two treatments for coronary heart disease.

A

-stents to keep the coronary arteries open
-statins to reduce blood cholesterol levels and slowdown, the rate of which fatty materials build up

50
Q

How can faulty heart valves be replaced?

A

using biological or mechanical valves

51
Q

How can heart failure be treated?

A

-a donor heart can be transplanted
-artificial hearts can be used to keep patients alive while waiting for a heart transplant or to allow the heart to recover

52
Q

What is cancer caused by?

A

uncontrolled cell division which can form masses called tumours

53
Q

What is the epidermis?

A

it covers the outer surfaces of the plant for protection

54
Q

What is the palisade mesophyll?

A

the main site of photosynthesis in the leaf

55
Q

What is the spongy mesophyll?

A

air spaces between the cells, allow gases to diffuse through the leaf

56
Q

What are xylem vessels?

A

transport, water and minerals through the plant from roots to leaves. Also support the plant.

57
Q

what are phloem vessels?

A

they transport dissolved food materials through the plant

58
Q

What is the meristem tissue?

A

found mainly at the tips of the roots and shoots where it can produce new cells for growth

59
Q

What is the function of the stomata?

A

allow the diffusion of gases in and out of the leaf and can be opened and closed by guard cells

60
Q

What is transpiration?

A

the loss of water from the leaves

61
Q

What factors affect the rate of transpiration?

A

-temperature
-air flow
-light intensity
-humidity

62
Q

Why are the stomata closed at night?

A

carbon dioxide is not needed for photosynthesis, so closing the stomata reduces water loss

63
Q

What happens to the guard cells and stomata when water is plentiful?

A

guard cells take up water and bend; stomata open, so gases for photosynthesis are free to move in and out of the stomata along with water from transpiration

64
Q

What happens to the guard cells and stomata when water is scarce?

A

the stomata change shape and close. this stops the plant from losing more water through transpiration

65
Q

What is translocation?

A

the movement of food through phloem tissue